In general, a pipeline can be installed with a horizontal drilling apparatus under a barrier, such as highway, road, waterway, building, or other surface obstruction without disturbing the barrier. Installation of the pipeline under the barrier typically entails forming a pilot bore under the barrier and then enlarging the pilot bore with a boring head, also known as a reamer or a hole opener. A pipeline section can be advanced behind the boring head and drilling liquids can be supplied to the boring operation through the pilot bore.